Most of the conventional beach chairs are of the lying-chair type. However, after using it for a period. it is found that this type of beach chair has the disadvantage of having large volume after being folded up. thus causing inconvenience in carrying along, besides, it has also the disadvantage of being unable to be placed in an stable condition on the beach ground. Owing to the above mentioned disadvantages, many improved products have been designed, such as "field-use spring bed", etc. Basically, these are only simple type of beddings, easy to be rolled up so that their volume can be reduced to the minimum. This is especially important when groups of people (such as family groups) travel around. However, in practical application, the above mentioned products still have the following defects:
1. In application, the bed surface must be aligned in horizontal level, that is, these products can only be used as lying beds which are not suitable for tourists because what the tourists need is a couch the upper half of which should be able to be elevated for a certain angle, so that the tourists can read or enjoy the nearby scenery. Therefore, the above mentioned products cannot meet the practical requirements for the field use to the best effect.
2. The manufacturer of the above mentioned products claimed that because of having the elastic triangular supporting body constructed by assembling the supporting rods at the two ends of the base frame, together with the elastic elements, their products can overcome the difficulty of using the products on irregular terrains. As a matter of fact, the above mentioned supporting frame and elastic elements is mainly designed for maintaining the bed-surface in a level and smooth condition, and is not designed for overcoming the irregularity of the ground surface. Since the supporting frame itself is also of the rigid-body design, there is no way to give the supporting frame some flexibility to follow the irregular shape of the ground surface. If the supporting rod is designed to have some elasticity, then, it will not be able to sustain the weight of the human body, and will have the possibility of being bent and deformed. Therefore, the above mentioned products also have the disadvantage of being limited in application by the irregularity of the ground surface.
3. Another disadvantage of the above mentioned products is that it is very inconvenient for the users to assemble the elements together. This is because of the fact that during assembly, the elastic elements at the two ends of the base frame must be pulled with considerable force. It is very difficult to do the job, especially for one person.
In view of the above mentioned disadvantages of the conventional couch, the inventor worked hard to study and improve, and succeeded in presenting this invention. The main purpose of this invention is to design a kind of couch suitable to be used indoors and outdoors. In other words, besides the advantage of being easily rolled up and conveniently carried along, this invention due to its two-section construction, can have the advantage of elevating the rear couch surface to a certain degree as the user likes, so that this couch can be used to its best functional limit, and it can also provide the user with the enjoyment of sitting and lying at his leisure time.
Another purpose of this invention is to provide the supporting rods at the two ends of the base frame, with a kind of two-section screw-thread design, so that the height of the base frame can be adjusted according to the condition of the ground surface. The result is that the couch-surface can be kept in a level and smooth condition under any circumstances, and therefore, it is comfortable for the user to sit on or lie down.
Still another purpose of this invention is to provide a new type of design of the three sets of the base frame which can be bent as if they were made of two portions. Besides, when necessary, the two portions can also be put in alignment and fixed automatically. This can be done only by pushing the handle downward so that the above mentioned two portions can be aligned and fixed correctly and the couch surface will be stretched tightly. Thus, it is very easy for the user to assemble the couch body without making much effort.